Blood and stool samples will be collected prior to vaccination, and 7 days after intake of each dose of the cholera vaccine and 7 days after the intake of last dose of typhoid vaccine, and the volumes to be sampled for immunological assays have been described in Appendix 2. The participants will not be allowed to eat or drink from one hour before and one hour after intake of the vaccine. To assess the effect of zinc on immune response to typhoid vaccine in young children, supplementation will be initiated 2 weeks before the first dose and will continue up to 21 days after the last (third) dose of typhoid vaccine (that is for a total of 40 days).